Spicules are best described as?

Spicules are best described as?

• A. Nerves
• B. Muscles
• C. Small, needle-like structures found in some sponges that provide structural support
• D. Pigment cells

Answer: (C)

Spicules are the rigid skeletal elements that give many sponges their shape and structural support. They’re usually tiny, needle-like particles made of silica or calcium carbonate that form a framework helping the sponge hold its form in moving water. Some sponges also have spongin, a flexible protein, but spicules provide the solid skeleton. Sponges lack true nerves and muscles, so those options don’t describe their biology, and pigment cells aren’t the defining feature here.